Calibrated Anchor Chain - What is the correct calibration?

PURCHASE Calibrated Anchor Chain

6mm, 7mm, 8mm, 10mm and 13mm chain calibrated to DIN766 plus 10mm and 12mm chain calibrated to ISO4565

We are very keen to help so please contact us by telephone or e-mail if you are not sure which calibration you need.

Each size and calibration is available in lengths cut to order from 1 metre up to 200 metres.

The simplest way to check that you are buying the correct calibration is to take a measurement from your existing chain, providing of course that it fits correctly.

How to measure Anchor Chain

We measure 10 links because, in practice, it is difficult to measure one link accurately enough.

The links should be laid out flat and pulled tight.

Measure from the outside edge to outside edge.

Measure a section that is in as reasonable a condition as possible i.e. not worn or corroded

Comparison of 10 Link Chain Measurements between Manufacturers
AQUA4/AQUA7Titan Grade 40Lofrans Grade 40MF Grade 40MF DAMS Grade 70
6mm DIN766190 mm195 mm 193mm
7mm DIN766228 mm 228mm
8mm DIN766250 mm253 mm253 mm 253mm 253mm
10mm DIN766295 mm297 mm298 mm 295mm 295mm
10mm ISO4565315 mm316 mm318 mm 317mm 317mm
12mm ISO4565375 mm375 mm
5/16" US Specification275 mm

These are Jimmy Green measurements taken from our actual stock here in Beer.
There is room for a little tolerance because the measurement is over 10 links.

If your existing chain is old and worn then the measurement over 10 links may be a little longer than Jimmy Green new stock by a small percentage.
By the same token, the dimaeter of the links on your existing chain may have expanded due to corrosion or rust, making the measurement a little shorter than a new chain.

If your chain falls between the measurement for 8mm DIN766 and 10mm DIN766, it may be 5/16" US Specification.
This is 8.7mm chain with a 26.1mm pitch:

Calibrated Anchor Chain, USA Dimensions and Laod Limits

The length for 10 links of 5/16" US will therefore be approximately 275mm-280mm (26.1 x 10 Plus 2 x 8.7 = 278.4)

The normal measurement range for each calibration is listed in the chart below:

Calibrated chain measurement range for each calibration
CalibrationSize/DiameterPitch10 links
6mm DIN7666mm18.5mm190-195mm
7mm DIN7667mm22mm228mm
8mm DIN7668mm24mm250-253mm
10mm DIN76610mm28mm295-298mm
10mm ISO10mm30mm313-318mm
12mm ISO12mm36mm375mm
5/16" USA8.7mm26.1mm275mm

Size/Diameter refers to the diameter of the bar that each link is made from, so don't measure the welded part.

Pitch refers to the inside length of each link.

The 10 links should be measured from outside edge to outside and the results can differ slightly according to the manufacturer.

N.B. Both DIN766 and ISO4565 allow a small tolerance in the link dimensions.

Gypsys are generally manufactured to cope with a little variation.

It isn't possible to give that variation a specific figure, but 2% should normally be fine.

The classic problem that crops up the most often is the 'wrong' 10mm chain for the gypsy.
The difference between DIN766 and ISO4565 is approximately 2mm on each link and this will definitely make the chain 'jump' under load.

Some modern gypsys are cleverly designed to cope with greater variation in pitch.

If you are starting from scratch i.e. you have a windlass gypsy but no chain that fits, bearing in mind that it doesn’t matter how old and rusty it is as long as it fits, then it is more difficult but we can still help.

Examine the gypsy to see if there is a definitive manufactuer stamp or marking - you may need to remove it from the windlass for a proper check

We can research the windlass and gypsy for you to narrow down the options and send you a short sample to lay in the pockets of the gypsy.

You can purchase 10 Links of Sample Anchor Chain to establish your calibration

You are looking for each link to fit snugly into a pocket.

If you can detect that the links will become out of kilter with the pockets on the gypsy, then the chain is probably not the correct calibration and it will 'jump' under load.

If the sample is not conclusive we can send you a longer (returnable) length which you can rig up with some rope for a practical trial under load.

We make every possible effort to send out the correct calibration because a little time spent before despatch is much better than trying to sort out the mess afterwards if it doesn’t fit.
Chain is heavy and is clearly not only expensive, but also tiresome to move around unnecessarily.

Carriers also make a surcharge for collection so that returning heavy parcels becomes even more expensive than the original carriage cost.

Customers should be aware that once we have cut a piece of chain (or rope for that matter) to length for you then the ‘distance rules for selling’ do not apply so it’s best not to leave anything to chance.
Essentially, this means that if you have made a mistake with your order then you are not entitled to a refund.
Under our returns policy you would be offered a credit or partial credit against your return of the goods.

If you are exchanging or better still upgrading in the process it will certainly help your case regarding the credit allowable.
N.B. this does not affect your statutory rights. If we have made an error on your order and sent the wrong goods or the goods we have sent are faulty, then you are, of course, entitled to a refund.

Dimensions for individual links of calibrated chain. Calibrated Anchor Chain - Dimensions

Calibrated Anchor Chain Information